public class MathUtil {
    public static int add(int a, int b) {
        return a + b;
    }
    public static int sub(int a, int b) {
        return a - b;
    }
    public static int mul(int a, int b) {
        return a * b;
    }
    public static int div(int a, int b) { return a / b;}
    public static int square(int a) { return a *a;}

}
